Solar Cell Passivation Layer Uniformity on Textured Substrates

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Solution Overview

Problem

The thickness uniformity of film layers on textured silicon substrates in solar cells is deteriorating due to excessive stacking, leading to chromatic aberration, reduced open-circuit voltage, and decreased conversion efficiency.

Innovation Solution

A solar cell design with a first passivation layer on a pyramid-shaped microstructure, where the length of the bevel edge is controlled between 0.4 µm and 1.9 µm to ensure uniform deposition, and the passivation layer's non-uniformity is maintained at ≤4%, improving the match with metal paste and enhancing the antireflection effect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple film layers are stacked to achieve passivation and antireflection, then the passivation effect and antireflection performance are improved, but the deposition uniformity on textured pyramid surface deteriorates

Engineering Contradiction:
Improvepassivation effectVSAvoiddeposition uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent extracts the texture structure from the substrate surface to create pyramid-shaped microstructures with controlled bevel edges. By removing material to form these specific geometric features, the patent enables uniform film deposition while maintaining effective passivation and antireflection properties. The extraction of the texture pattern allows subsequent films to deposit uniformly on the modified surface geometry.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies local quality by creating pyramid-shaped microstructures with specific bevel edge lengths (0.4-1.9 μm) at different locations on the substrate. This localized geometric modification ensures that film layers deposit uniformly on the textured surface, while different regions of the pyramid structures provide optimized passivation and antireflection characteristics.

Inventive Principle:
Principle #3Local quality

2Reliability

If multiple film layers are stacked to achieve passivation and antireflection, then the antireflection performance is improved, but the appearance color uniformity deteriorates

Engineering Contradiction:
Improveantireflection performanceVSAvoidappearance color uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent extracts the texture structure to form pyramid-shaped microstructures that control light interaction. By removing material to create these specific geometric features with controlled bevel edges, the patent achieves uniform antireflection performance while maintaining consistent appearance color across the solar cell surface.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies local quality by creating pyramid structures with specific bevel edge dimensions (0.4-1.9 μm) that provide localized optical control. This ensures uniform antireflection performance and consistent appearance color across different regions of the solar cell while maintaining effective light management.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the bevel edge length is not controlled, then the manufacturing process is simpler, but the passivation layer thickness uniformity deteriorates

Engineering Contradiction:
Improveprocess simplicityVSAvoidpassivation layer thickness uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling the bevel edge length of pyramid structures within a specific range (0.4-1.9 μm). This parameter control ensures that subsequent passivation layer deposition achieves uniform thickness (non-uniformity ≤4%) while maintaining manufacturing feasibility through established texturing processes.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If the passivation layer thickness is non-uniform, then the deposition process is faster, but the open-circuit voltage decreases

Engineering Contradiction:
Improvedeposition speedVSAvoidopen-circuit voltage
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-forming pyramid-shaped microstructures with controlled bevel edges (0.4-1.9 μm) on the substrate before depositing the passivation layer. This preliminary texturing ensures that subsequent fast deposition processes produce uniform film thickness (non-uniformity ≤4%), thereby maintaining high open-circuit voltage while enabling rapid manufacturing.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach improves the passivation effect, increases open-circuit voltage, and boosts conversion efficiency by ensuring better matching between the passivation layer and metal paste, thereby enhancing the solar cell's performance.

Implementation Method 1

a first passivation layer located on the first texture structure of the semiconductor substrate. The first texture structure includes a pyramid-shaped microstructure, a length of a bevel edge of the pyramid-shaped microstructure is C μm, and 0.4≤C≤1.9. A non-uniformity of the first passivation layer is N≤4%

Methodology Applied
Scientific EffectGeometric control of deposition:

Implementation Method 2

a first passivation layer located on the first texture structure of the semiconductor substrate... improves the passivation effect

Methodology Applied
Scientific EffectPassivation effect:

Implementation Method 3

improving the match with metal paste and enhancing the antireflection effect

Methodology Applied
Scientific EffectAntireflection effect: Anti-Reflective Coating

Data Source

PatentEP4148808A1Solar cell, method for manufacturing solar cell, and photovoltaic module
Publication Date: 2023.03.15 ZHEJIANG JINKO SOLAR CO LTD
  • EP4148808A1 patent drawingFigure 1~2a
  • EP4148808A1 patent drawingFigure 2b~2c
  • EP4148808A1 patent drawingFigure 2d~2e

AI summary

Provided are a solar cell, a method for manufacturing a solar cell and a photovoltaic module. The solar cell includes a semiconductor substrate including a surface having a first texture structure and a first passivation layer located on the first texture structure of the semiconductor substrate. The first texture structure includes a pyramid-shaped microstructure, a length of a bevel edge of the pyramid-shaped microstructure is C µm, and 0.4≤C≤1.9. A nonuniformity of the first passivation layer is N≤4%, and N=(Dmax-Dmin)/Dmax. Dmax is a maximum thickness of the first passivation layer on the pyramid-shaped microstructure, and Dmin is a minimum thickness of the first passivation layer on the pyramid-shaped microstructure.